fmt/include/fmt/fmtlog.h

314 lines
16 KiB
C++

#ifndef FMT_FMTLOG_H_
#define FMT_FMTLOG_H_
#include "format.h"
#include <tuple>
namespace fmtlog {
using namespace fmt;
template <typename Context> struct basic_format_entry {
protected:
using char_type = typename Context::char_type;
using format_arg = typename basic_format_args<Context>::format_arg;
using arg_destructor = void (*)(void *p);
basic_string_view<char_type> format_;
unsigned long long desc_;
arg_destructor dtor_;
FMT_CONSTEXPR basic_format_entry(basic_string_view<char_type> format) : format_(format), desc_(0), dtor_(0) {}
const format_arg* get_format_args() const;
template <typename OutIt, typename T = OutIt>
using enable_out = std::enable_if_t<fmt::detail::is_output_iterator<OutIt, char_type>::value, T>;
public:
void destruct() { if (dtor_) dtor_(this); }
// libfmt public APIs
std::basic_string<char_type> format() const { return fmt::vformat(format_, {desc_, get_format_args()}); }
template <typename OutIt>
auto format_to(OutIt out) const -> enable_out<OutIt> {
return fmt::vformat_to(out, format_, {desc_, get_format_args()});
}
template <typename OutIt>
auto format_to_n(OutIt out, size_t n) const -> enable_out<OutIt, format_to_n_result<OutIt>> {
return fmt::vformat_to(fmt::detail::truncating_iterator<OutIt>(out, n), format_, {desc_, get_format_args()});
}
size_t formatted_size() const {
fmt::detail::counting_buffer<> buf;
format_to(buf);
return buf.count();
}
void print(std::FILE* file = stdout) const { return fmt::vprint(file, format_, {desc_, get_format_args()}); }
};
template <typename Context, typename... Args> struct format_entry : basic_format_entry<Context> {
using entry = basic_format_entry<Context>;
format_arg_store<Context, Args...> arg_store_;
template <typename S>
FMT_CONSTEXPR format_entry(const S& format_str, const Args&... args) : entry(to_string_view(format_str)), arg_store_(args...) {
entry::desc_ = arg_store_.desc;
}
FMT_CONSTEXPR void set_dtor(typename entry::arg_destructor dtor) { this->dtor_ = dtor; }
};
template <typename Context>
inline const typename basic_format_entry<Context>::format_arg* basic_format_entry<Context>::get_format_args() const {
union obfuscated_args {
const fmt::detail::value<Context>* values_;
const format_arg* args_;
intptr_t pointer_; // more efficient to add integer with size, as the compiler is able to avoid emitting branch
} args;
auto& entry = static_cast<const format_entry<Context>&>(*this);
args.values_ = entry.arg_store_.data_.args_;
if (entry.desc_ & fmt::detail::has_named_args_bit) {
args.pointer_ += (desc_ & fmt::detail::is_unpacked_bit) ? sizeof(*args.args_) : sizeof(*args.values_);
}
return args.args_;
}
//
// A stored entry looks like:
// -----------------------------------------------------------------------
// | basic_format_entry | arg_store | stored_objs... | stored_buffers... |
// -----------------------------------------------------------------------
//
namespace detail {
enum class store_method {
numeric, // stored by libfmt as numeric value, no need for extra storage
object, // stored by libfmt as object, copy/move construct the object manually (requires properly calling destructor)
buffer, // string/hexdump, store the string/binary trivially as buffer.
constexpr_str // compile-time string, can be stored as pointer directly (requires c++20 is_constant_evaluated())
};
template <store_method method> using store_method_constant = std::integral_constant<store_method, method>;
using store_as_object = store_method_constant<store_method::object>;
using store_as_buffer = store_method_constant<store_method::buffer>;
template <typename Type>
using stored_as_numeric = std::integral_constant<bool, fmt::detail::is_arithmetic_type(Type::value) || Type::value == fmt::detail::type::pointer_type>;
template <typename Type>
using stored_as_string = std::integral_constant<bool, Type::value == fmt::detail::type::cstring_type || Type::value == fmt::detail::type::string_type>;
template <typename T> struct is_basic_string : std::false_type {};
template <typename C, typename T, typename A> struct is_basic_string<std::basic_string<C, T, A>> : std::true_type {};
template <typename Type, typename T>
using stored_as_string_object = std::integral_constant<bool, stored_as_string<Type>::value && is_basic_string<std::remove_reference_t<T>>::value && std::is_rvalue_reference<T>::value>;
struct custom_store_method_checker {
template <typename Arg, typename Context, typename RawT = std::decay_t<Arg>, typename Formatter = typename Context::template formatter_type<RawT>>
static std::enable_if_t<has_formatter<RawT, Context>::value, std::tuple<std::true_type, decltype(Formatter::store(std::declval<char*&>(), std::declval<Arg>()))>> test(double);
template <typename Arg, typename Context, typename RawT = std::decay_t<Arg>, typename Formatter = typename Context::template formatter_type<RawT>>
static std::enable_if_t<has_formatter<RawT, Context>::value, std::tuple<std::false_type, decltype(Formatter::store(std::declval<char*>(), std::declval<Arg>()))>> test(int);
template <typename Arg, typename Context>
static std::tuple<std::false_type, store_as_object> test(...);
};
template <typename Arg, typename Context>
struct custom_store_method {
using transformed_type = typename std::tuple_element<1, decltype(custom_store_method_checker::template test<Arg, Context>(0))>::type;
static constexpr bool custom_store = std::tuple_element<0, decltype(custom_store_method_checker::template test<Arg, Context>(0))>::type::value && !std::is_same_v<transformed_type, store_as_object>;
using store_type = std::conditional_t<std::is_same_v<transformed_type, store_as_object>, store_as_object, store_as_buffer>;
};
template <typename Arg, typename Context, typename Type = fmt::detail::mapped_type_constant<std::remove_reference_t<Arg>, Context>>
struct stored_method_constant : std::integral_constant<store_method, // using class (not template using) to allow easier partial specialization.
stored_as_numeric<Type>::value ? store_method::numeric :
stored_as_string<Type>::value ? (stored_as_string_object<Type, Arg>::value ? store_method::object : store_method::buffer) :
// store_method::object> {};
custom_store_method<Arg, Context>::store_type::value> {};
struct stored_objs_dtor_base : std::integral_constant<size_t, 0> {
static void destruct(void* p) {}
};
template <typename Base, ptrdiff_t offset, typename RawT>
struct stored_objs_dtor_gen : std::integral_constant<size_t, offset + sizeof(RawT)> {
static void destruct(void* p) {
reinterpret_cast<RawT*>((reinterpret_cast<char*>(p) + offset))->~RawT();
Base::destruct(p);
}
};
template <typename Context, ptrdiff_t offset, typename Base, typename T, typename... Args>
struct stored_objs_dtor_select {
using RawT = std::remove_reference_t<T>;
using type = std::conditional_t<stored_method_constant<T, Context>::value == store_method::object,
typename stored_objs_dtor_select<Context, offset + sizeof(RawT), stored_objs_dtor_gen<Base, offset, RawT>, Args...>::type,
typename stored_objs_dtor_select<Context, offset, Base, Args...>::type>;
};
template <typename Context, ptrdiff_t offset, typename Base>
struct stored_objs_dtor_select<Context, offset, Base, void> { using type = Base; };
template <typename Context, ptrdiff_t offset, typename... Args>
using stored_objs_dtor = typename stored_objs_dtor_select<Context, offset, stored_objs_dtor_base, Args..., void>::type;
// Collects internal details for generating index ranges [MIN, MAX)
template <size_t...> struct index_list {};
// Induction step
template <size_t MIN, size_t N, size_t... Is>
struct range_builder : public range_builder<MIN, N - 1, N - 1, Is...> {};
// Base step
template <size_t MIN, size_t... Is> struct range_builder<MIN, MIN, Is...> { typedef index_list<Is...> type; };
// Meta-function that returns a [MIN, MAX) index range
template<size_t MIN, size_t MAX>
using index_range = typename range_builder<MIN, MAX>::type;
template <typename... Args>
struct arg_transformer {
using arg_tuple = std::tuple<Args...>;
template <size_t N> using arg_at = typename std::tuple_element<N, arg_tuple>::type;
using type_tuple = std::tuple<std::decay_t<Args>...>;
template <size_t N> using type_at = typename std::tuple_element<N, type_tuple>::type;
template <size_t N> using size_at = std::integral_constant<size_t, sizeof(type_at<N>)>;
template <typename Context, size_t N> using objsize_at = std::conditional_t<stored_method_constant<arg_at<N>, Context>::value == store_method::object, size_at<N>, std::integral_constant<size_t, 0>>;
template <typename Context, size_t N> struct objsizesum_at : std::integral_constant<size_t, std::conditional_t<N == 0, std::integral_constant<size_t, 0>, objsizesum_at<Context, N - 1>>::value + objsize_at<Context, N>::value> {};
template <typename Context, size_t N> using objoffset_at = std::conditional_t<N == 0, std::integral_constant<size_t, 0>, objsizesum_at<Context, N - 1>>;
};
template <typename Arg, typename Context, typename Type = fmt::detail::mapped_type_constant<std::remove_reference_t<Arg>, Context>>
using transformed_arg_type = std::conditional_t<custom_store_method<Arg, Context>::custom_store, typename custom_store_method<Arg, Context>::transformed_type,
std::conditional_t<stored_as_string<Type>::value && !stored_as_string_object<Type, Arg>::value, basic_string_view<typename Context::char_type>, std::add_const_t<std::remove_reference_t<Arg>>&>
>;
template <typename Context, typename... Args>
struct format_entry_constructor {
using Entry = format_entry<Context, std::decay_t<transformed_arg_type<Args, Context>>...>;
using Dtor = stored_objs_dtor<Context, sizeof(Entry), Args...>;
using Trans = arg_transformer<Args...>;
template <typename S>
static size_t construct(void* buf, const S& format_str, Args... args) {
return format_entry_constructor<Context, Args...>(buf, format_str, range(), std::forward<Args>(args)...).get_total_size();
}
private:
using range = typename range_builder<0, sizeof...(Args)>::type;
template <typename S, size_t... Indice>
constexpr format_entry_constructor(void* buf, const S& format_str, index_list<Indice...>, Args... args) : pEntry(reinterpret_cast<char*>(buf)), pBuffer(get_buffer_store(buf)) {
auto p = new(buf) Entry(format_str, store<Indice>(std::forward<Args>(args))...);
p->set_dtor(Dtor::value ? Dtor::destruct : nullptr);
}
template <size_t N> using arg_at = typename Trans::template arg_at<N>;
template <size_t N> transformed_arg_type<arg_at<N>, Context> store(typename Trans::template arg_at<N> arg) {
using Arg = typename Trans::template arg_at<N>;
using select_store_method = custom_store_method<Arg, Context>;
using MappedType = fmt::detail::mapped_type_constant<std::remove_reference_t<Arg>, Context>;
if constexpr (select_store_method::custom_store == true) {
using Formatter = typename Context::template formatter_type<std::decay_t<Arg>>;
// fmt::print("store custom arg {} @ {}\n", N, (void*)pBuffer);
return Formatter::store(pBuffer, std::forward<Arg>(arg));
}
else if constexpr (stored_as_string<MappedType>::value && !stored_as_string_object<MappedType, Arg>::value) {
// fmt::print("store string arg {} @ {}({})\n", N, (void*)pBuffer, fmt::detail::arg_mapper<Context>().map(std::forward<Arg>(arg)));
return copy_string(pBuffer, fmt::detail::arg_mapper<Context>().map(std::forward<Arg>(arg)));
}
else if constexpr (stored_as_numeric<MappedType>::value) {
return std::forward<Arg>(arg);
}
else {
char* const pobjs = pEntry + sizeof(Entry);
char* const pobj = pobjs + Trans::template objoffset_at<Context, N>::value;
using Type = typename Trans::template type_at<N>;
auto p = new(pobj) Type(std::forward<Arg>(arg));
return *p;
}
}
static basic_string_view<typename Context::char_type> copy_string(char*& pBuffer, const typename Context::char_type* cstr) {
if constexpr (std::is_same_v<typename Context::char_type, wchar_t>) {
wchar_t* pStart = reinterpret_cast<wchar_t*>(pBuffer);
wchar_t* pEnd = wcpcpy(pStart, cstr);
pBuffer = reinterpret_cast<char*>(pEnd);
// fmt::print("copied wstring ({}) @ {}\n", basic_string_view<wchar_t>(pStart, pEnd - pStart), (void*)pStart);
return basic_string_view<wchar_t>(pStart, pEnd - pStart);
}
else {
char* pStart = pBuffer;
char* pEnd = stpcpy(pStart, cstr);
pBuffer = pEnd;
// fmt::print("copied string ({}) @ {}\n", basic_string_view<char>(pStart, pEnd - pStart), (void*)pStart);
return basic_string_view<char>(pStart, pEnd - pStart);
}
}
static basic_string_view<typename Context::char_type> copy_string(char*& pBuffer, basic_string_view<typename Context::char_type> sv) {
typename Context::char_type* pStart = reinterpret_cast<typename Context::char_type*>(pBuffer);
size_t size = sizeof(typename Context::char_type) * sv.size();
std::memcpy(pStart, sv.data(), size);
pBuffer += size;
return basic_string_view<typename Context::char_type>(pStart, sv.size());
}
static constexpr char* get_buffer_store(void* buf) {
char* const pentry = reinterpret_cast<char*>(buf); // entry will be constructed here
char* const pobjs = pentry + sizeof(Entry); // objects will be stored starting here
char* const pbufs = pobjs + get_obj_size(); // buffers will be stored starting here
// fmt::print("creating custom arg entry @ {}, {}, {}\n", (void*)pentry, (void*)pobjs, (void*)pbufs);
return pbufs;
}
static constexpr size_t get_obj_size() { return Trans::template objsizesum_at<Context, sizeof...(Args) - 1>::value; }
constexpr size_t get_total_size() const { return pBuffer - pEntry; }
char* const pEntry;
char* pBuffer;
};
template <typename Context>
struct entry_destruct_sentry {
using Entry = basic_format_entry<Context>;
entry_destruct_sentry(Entry& entry) : entry_(entry) {}
~entry_destruct_sentry() { entry_.destruct(); }
Entry& entry_;
};
}
template <typename S, typename... Args, typename Char = char_t<S>>
inline size_t store_format_entry(void* buf, const S& format_str, Args&&... args) {
using Context = buffer_context<Char>;
using Constructor = detail::format_entry_constructor<Context, Args&&...>;
return Constructor::construct(buf, format_str, std::forward<Args>(args)...);
}
template <typename Context>
inline auto format_entry_to_string(basic_format_entry<Context>& entry) -> decltype(entry.format()) {
detail::entry_destruct_sentry<Context> _(entry);
return entry.format();
}
template <typename OutIt, typename Context>
inline auto format_entry_to(OutIt out, basic_format_entry<Context>& entry) -> decltype(entry.format_to(out)) {
detail::entry_destruct_sentry<Context> _(entry);
return entry.format_to(out);
}
template <typename OutIt, typename Context>
inline auto format_entry_to_n(OutIt out, size_t n, basic_format_entry<Context>& entry) -> decltype(entry.format_to_n(out, n)) {
detail::entry_destruct_sentry<Context> _(entry);
return entry.format_to(out, n);
}
template <typename Context>
inline void print_format_entry(std::FILE* f, basic_format_entry<Context>& entry) {
detail::entry_destruct_sentry<Context> _(entry);
entry.print(f);
}
template <typename Context> inline void print_format_entry(basic_format_entry<Context>& entry) { print_format_entry<Context>(stdout, entry); }
}
#endif